This project has three areas of investigation. The applicant proposes initially to study the development of electron dense pigmentary granules which appear in neurons following the digestion of retroviruses by phagosomes. He will also examine the induction of amyloid and neuritic plaques which occurs following the infection of VM mice by the 87A strain of the scrapie agent. These studies will concentrate on the origin, evolution and nature of the amyloid components of the induced plaques. He also proposes to elute immunoglobulins from autopsy-derived Alzheimer diseased brains. Finally, it is noted that the investigator and his associates will provide a considerable amount of support (morphologic evaluations) to the other projects of this proposed program. The techniques involve electron microscopy, immunoelectron microscopy, and immunohistochemistry.